Open Grid Forum 20 Report
Omer Rana – GridNet ID: 107
School of Computer Science and Welsh eScience Centre
Cardiff University, UK
o.f.rana@cs.cardiff.ac.uk
This report provides an overview of my involvement in research and working
groups at the Open Grid Forum (OGF) 20 meeting in Manchester, May 7–11,
2007. A key message from this particular meeting was the increasing focus on
Web 2.0 and social network-based technologies to support collaboration between
application users. Web 2.0 technologies (such as the Google Programming API,
AJAX, JSON, etc) provide ease of use and development in comparison with
many of the existing Web Services specifications. I participated in the following
activities:
• Co-organizer: Dynamic Service Level Agreements Workshop
• Participant: SOKU Workshop
• Participant: GRAAP working group sessions
• Speaker: Workflow working group session
• Participant: SAGA API session
• Participant: Service Level Terms for OGSA BoF
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GRAAP
The GRAAP working group involved three sessions – focusing on the currently
released specification of WS-Agreement. The first session was dedicated to
presentations from European projects in the area – such as AssessGrid (focusing
on aspects of risk assessment in service provisioning).
The second session was focussed on discussion of Negotiation protocols that
can be used alongside WS-Agreement. The discussion focused on two key
points: (1) whether a 2 phase commit protocol was a useful protocol to support; (2) whether negotiation should be part of WS-Agreement, or whether it
could be something undertaken outside the specification (but could make use
of terms/schema of WS-Agreement). The key concern regarding issue (1) related to whether reliable messaging could be guaranteed when a provider was
making an offer to a client. It was argued that message delays could lead to a
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provider having to wait for approval from a client, thus reducing the ability of
a provider to offer resources to other clients. Relationship with such models in
databases was also discussed. Issue (2) remains an open concern in the GRAAP
working group, as some feel that negotiation should be an integral part of the
WS-Agreement specification. Something that I disagree with. Especially, as
this is likely to make the specification more complex.
The final session of GRAAP focused on identifying interoperability experiments that needed to be undertaken once the GRAAP specification had been
approved. Discussion in this session mainly focused on identifying what type
of interoperability work was necessary, and what needed to be implemented to
demonstrate interoperability. Currently, four research groups are involved in
implementing the WS-Agreement specification – to varying extents. These include Fraunhofer Institute, University of Stuttgart, Tech. University of Berlin
and Cardiff University. It was generally agreed that coordination between these
groups was necessary, and it would be useful to identify what interoperability
tests could be undertaken between these groups. A document has been started
that outlines these interoperability tests, the first version of which was discussed
and started at OGF20.
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Workshop: Dynamic SLAs
The Dynamic SLAs workshop was organized to emphasise the importance of
identifying and managing SLAs where: (1) Service Level Objectives (SLOs)
can change during service execution; (2) an SLO description scheme allows for
changes in SLOs during service provisioning, to prevent an excessive number of
violations to be raised. The workshop included a number of presentations from
European projects (mainly), such as AssessGrid, BREIN, BeinGrid, Grid Job
Scheduling and HPC4U. A panel session to assess the importance of dynamic
SLAs with reference to business and scientific applications was organized – and
included three panelists.
Three outcomes of the panel session were: (i) it was necessary to precisely
define what constituted “dynamic” SLAs – as compared to “static” SLAs; (ii) it
was useful to consider intervals when defining SLA properties – as this was useful
to ensure that a provider was able to deal with small changes in provisioning and
still remain within valid limits; (iii) identify which communities would benefit
from dynamic SLAs – and whether suitable use cases could be provided to guide
the development of such SLAs. It is expected that a use case document will be
produced to address issues (ii) and (iii) in particular.
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Sharing Workflows Workshop
The sharing workflows workshop focused on the need for sharing workflow descriptions and subsequently mechanisms to enact workflows across different engines. A variety of views were presented – from the need to support semantic
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annotations on abstract workflow graphs to support for plug-ins that allow workflow enactment to take place in their “native” environment. The use of a portal
to coordinate the execution of a workflow was also stressed, where the portal
would interact with workflow enactment engines, allowing a workflow to be split
across such engines.
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Evaluation from last report – from OGF19
From the OGF19 report, a number of possible activities to be carried out in
the future were highlighted. Below an assessment of the current state of these
activities is presented:
• A telecon. has been organized for February 16, 2007, to focus on discussing
interoperability tests that need to be carried out between two (or more) WSAgreement implementations. This telecon. has been intended to define the
basis for an information document on WS-Agreement interoperability.
Outcome: The telecon. was organized and led to the first working document outlining interoperability tests needed.
• A workshop at the National eScience Center in Edinburgh on February 19
and 20 with a particular focus on “Agent-based Grid Computing”. Service
Level Agreements will form one of the key topics of discussion. The workshop is funded by the EPSRC “Agentcities.UK” networkwith secretarial
support from NeSC. This workshop is jointly organized by Julian Padget
(Bath University) and me. Members of the Semantic Web community
(such as researchers in the EU TrustCom, EU OntoGrid, OMII Knoogle,
EPSRC DiscoveryNet, EU SORMA, EU Catnets and EU BREIN projects)
will be participating in the workshop). The event is therefore also intended
to provide cross fertilization between Semantic Grids and SLAs.
Outcome: The workshop was successfully organized with over
25 participants from the UK and Europe. TrustCom, OntoGrid,
OMII, DiscoveryNet, SORMA, Catnets, e-Rep, and other projects
were presented. A document outlining use cases of agent-based
approaches in Grid computing was started. Currently over 10
use cases have been identified.
• A workshop has been proposed at OGF20 in Manchester (in May 2007)
consisting of two 90-minute sessions. The focus at this workshop will be
on Dynamic Service Level Agreements. This workshop is to be jointly organized by Wolfgang Ziegler (Fraunhofer Institute), Philipp Weider (Jeulich
Research Center) and me.
Outcome: The workshop was successfully organized – and included participation of Karim Djemame (from Leeds University)
as a co-organizer.
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• A workshop at the IEEE/ACM “Autonomic Computing” conference at
Jacksonville (Florida) on “Policy-based Autonomic Computing”. A key
theme in this workshop is the relationship between policy specification and
Service Level Agreements. The workshop is jointly organized by Richard
Anthony (University of Greenwich), Duncan Johnston-Watt (Enigmatec
Corporation) and me.
Outcome: The workshop is going ahead – and is planned to take
place on June 14, 2007. A publication from Springer/Whitestein
will be produced.
• There will be a tutorial at the IEEE CCGrid 2007 conference in Rio de
Jenairo (Brazil) in May 2007. The tutorial is focused on Autonomic Grid
Computing and will be delivered by Salim Hariri (University of Arizona),
Manish Parashar (Rutgers University) and me. Over 20% of the tutorial
will be dedicated to Service Level Agreements.
Outcome: The tutorial was successfully delivered by Manish
Parashar and myself. Over 50+ people attended the tutorial.
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Future Activities
The following future activities are planned until the end of GridNet2 (December
2007):
• Workshop on “SLA Usage in Grids” (organizers: Wolfgang Ziegler (Fraunhofer Institute), Philipp Weider (Jeulich Research Center) and myself) at
ACM/IEEE Grid 2007 conference in Austin, Texas (September 2007).
• Workshop on “Economic Models for Grid Computing” (co-chairs: Dirk
Neumann (U. Karlsruhe), Mark Baker (U. Reading) and myself) at ACM/IEEE
Grid 2007 conference in Austin, Texas (September 2007).
• Additional work on use-case document outlining use of agent-based approaches in Grids.
• Additional work on interoperability tests and coordination between WSAgreement implementations.
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